Sprinkler drive

ABSTRACT

An oscillating sprinkler drive for pivotally moving the spray tube of an oscillating sprinkler in partial overlapping oscillational movements to facilitate even distribution of water over a rectangular area. The drive primarily comprises a drive cam and a follower arm which are operatively connected to the spray tube through conventional linkage. The cam is designed to reverse movement of the spray tube at preselected angular positions between angular limits set by the conventional linkage. By strategically locating these reversing points, more water may be directed toward the center of the spray pattern to compensate for the dwell of the spray tube at the angular limits.

United States Patent [191 Standal SPRINKLER DRIVE [76] Inventor: George M. Standal, 1916 San Fernando PL, Victoria, B.C.,

Canada [22] Filed: Oct. 24, 1972 [21] Appl. No.: 299,751

[451 Jan. 29, 1974 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Y. Mar Attorney, Agent, or Firm-Greek Wells et a1.

[5 7] ABSTRACT An oscillating sprinkler drive for pivotally moving the spray tube of an oscillating sprinkler in partial overlapping oscillational movements to facilitate even distribution of water over a rectangular area. The drive primarily comprises a drive cam and a follower arm which are operatively connected to the spray tube through conventional linkage. The cam is designed to reverse movement of the spray tube at preselected angular positions between angular limits set by the conventional linkage. By strategically locating these reversing points, more water may be directed toward the center of the spray pattern to compensate for the dwell of the spray tube at the angular limits.

9 C1aims,-10 Drawing Figures FIG 1 PMENIEDJANZSIG'M SHEET 1 BF 1 SPRINKLER DRIVE BACKGROUND OF THE INVENTION It has been found that most conventional lawn and garden sprinklers do not evenly distribute water, especially those designed to cover large areas. Possibly the most commonly used sprinkler for large areas is the oscillating type which distributes water in a substantially rectangular pattern. These sprinklers are commonly driven by the incoming water through a fluid motor, the drive shaft of which is operatively connected to a pivoted horizontal spray tube. As the drive shaft rotates, the spray tube oscillates between angular limits set by a linkage connecting the tube with the drive shaft. Generally the linkage is comprised of a crank fixed between a spray tube connecting arm and the drive shaft so that as the crank rotates, its motion is transmitted to the spray tube as oscillational movement rather thanrotational movement. Thedifficulty with such sprinklers-is the result of inherent physical characteristics of such crank driven linkages. The reversing movement of the spray tube occurs at and adjacent dead center positions of the crank and connecting arm. At these positions, rotational movement of the crank results in very little movement of the connecting arm and-spray tube. It

may therefore be seen that there is a considerable dwell of the spray tube at the angular limits of each'spray sweep. Further, the velocity of the spray tube increases as it approaches the central portion of the spray sweep. The result of such motion is that the ends of the spray pattern receive too much water while the central portion receives too little.

Various attempts have been made to redesign the above described oscillating sprinklers to facilitate efficient, even distribution of water over a large arearOne such apparatus is disclosed in US. Pat. No. 3,261,553 granted to J. Kooi and US. Pat. No. 3,063,646 granted to W. W. Ballard. I Both describe an oscillating type sprinkler operated by a cam rather than a crank. By utilizing a heart-shaped cam and a modified linkage Kooi and Ballard have been able to increase the velocity of the spray tube during the reversing movements at the angular limits. I have found that although the efficiency of these sprinklers has improved over the crank type, the central area of the sprinkler pattern still receives less water than the ends. I

The present invention was conceived to further improve the efficiency of oscillating sprinklers by dividing SUMMARY OF THE INVENTION The present invention comprises a motion transmitting assembly interposed in the drive train of an oscillating sprinkler, to cause the water from the sprinkler spray tube to cover a fractional portion of a preselected irrigated area as the spray tube progresses angularly between itspre-selected limits. By reversibly overlapping such fractional spray patterns, the 'water A BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an oscillating sprinkler;

FIG. 2 is an elevation view of the sprinkler illustrated in FIG. 1; I

FIG. 3 is a sectional view taken along line 33 in FIG. 2; and

FIGS. 4-9 are diagrammatic views illustrating various operational positions of the sprinkler drive; and

FIG. 10 is a view combining the movements illustrated'in FIGS. 4-9. I

DESCRIPTION OF A PREFERRED EMBODIMENT The present apparatus is presented as a mechanical modification of conventional oscillating type lawn sprinklers. The illustrated sprinkler is of the type commonly available for residential lawn and garden use,

being attached by hose to a source of water under pressure for irrigation usage. In such sprinklers, a supporting frame rests on the ground in a fixed position, and

water under pressure is directed to a longitudinal spray tube having a row of perforations through which long streams of water are directed outwardly in an arc. During application of water, the spray tube is oscillated or rocked back and forth to distribute the water across a generally rectangular surface area.

The spray tube is oscillated by a water-driven motor through reduction gearing and a drive assembly that converts the constant rotational movement of the motor drive shaft to an oscillating rocking movement of the spray tube. The drive assembly typically includes a selector dial by which the angular limits of oscillation of the spray tube can be manually set to a selected pattern of oscillation dependent upon the nature of the area being irrigated. The present disclosure is not concerned with the details of the motor mechanism or the dial adjustment, and is applicable to any available type of oscillating sprinkler having such common features. Many examples of such devices are commercially avail able and further mechanical details as to the motor or conventional dial adjustment .can be found by reference to the patents listed above.

Taking the generally conventional elements of the sprinkler first, it includes a bent tubular frame 10 that is adapted to rest upon the ground surface in a stationary location during use. This frame or base could be of any desired rigid structure capable of supporting the moving elements of the sprinkler. Mounted to the frame 10 is a sealed motor housing 11 that serves as a water receptacle and as a protective enclosure for the water-driven motor that powers the sprinkler.

An elongated curve spray tube 12 is pivotally mounted about a longitudinal axis by a bearing connection at one end within motor housing 11 and at the remaining end by an outer bearing 13 mounted to the frame 10. The mounting of the spray tube 12 within the motor housing 11. includes suitable gaskets to prevent leakage of water directed to the spray pipe 12. Within the motor housing 11 there is provided suitable diversion devices for directing water to the spray tube 12 after all or a part of the water flow has been utilized for turning the water wheel or turbine that acts as a motor. A hose connection 14 is provided for attachment to a garden hose or other suitable source of water under pressure.

The output of the water motor is in the form of a drive shaft 15 that protudesfrom the face of the motor housing 1 l, and which typically is located vertically beneath the spray tube 12. The longitudinal axis of the rotatable drive shaft 15 is parallel to the pivotal axis of the spray tube 12. A linkage assembly is operatively connected between the drive shaft 15 and spray tube 12 to convert the constant rotational movement of shaft 15 into oscillating angular movement of spray tube 12 about its respective axis. A crank arm 16 is fixed to the spray tube 12 and is pivotally connected to a rigid connecting link 18 by means of a rotationally adjustable dial 17. The pivotal connection between link 18 and crank arm 16 is shown at 19. The dial 17 is capable of angularly positioning the pivotal connection 19 at several locations about the center of the dial, whereby the limits of angular movement of spray pipe 12 can be varied to produce various types of spray patterns. By use of dial 17 one can conventionally set the sprinkler for a full pattern from one side of the center spray tube 12 to either side of the sprinkler. All of the above structure is generally conventional in such sprinklers, and further details with respect to these elements is not believed to be essential for a full understanding of the present improvements.

Referring now to the drawings, the modifications made with respect to the conventional sprinkler assembly relate to the substitution within the drive assembly of a cam and a follower, connecting drive shift 15 to link 18. All other elements of the sprinkler remain unchanged.

The cam, shown generally at 20, is affixed to drive shaft 15 for rotational movement therewith. Such movement of cam 20 is transmitted to link 18 by follower arm 21. Arm 21 is pivotably fixed at one end to frame 10 by a pivot pin 22. The pivot axis defined by pin 22 is parallel to and spaced elevationally below and to one side of the drive shaft axis. A second pivot 23, connects the other end of follower arm 21 on the other side of the drive shaft axis to the lower end of link 18.

A tension spring 24 is connected between housing 11 and the end of follower 21 adjacent pivot 23 to bias an upward projection 25 on follower 21 upwardly against cam 20. Projection 25 is positioned along the length of follower 21 adjacent pivot 23 to provide a leverage advantage to minimize strain'on the fluid motor.

It should be noted that'placement of the follower at the described location relative to the drive shaft facilitates its use with links 18 of conventional sprinklers. It is well understood that follower 21 could be positioned elsewhere on housing 11 or frame 10 without adversely affecting the operation of the sprinkler.

Cam 20 includes a curvilinear periphery or cam surface of unique design which constitutes the primary feature of my invention. The periphery of cam 20 includes three convex sections and three concave sections with respect to the axis of drive shaft 15. The concave surfaces are interspersed between convex surfaces and are spaced angularly about the shaft axis. Each convex surface includes an apex or point of maximum radial distance from the shaft axis, which defines a reversing point in the oscillatory movement of spray tube 12. The distance from the shaft axis to each apex defined the angular position of the spray tube at the reversing point in the movement of tube 12 as the cam rotates. Each reversing point is shown graphically in FIGS. 4, 6 and 8 respectively.

Each concave section has a bottom point or a point on that section of a minimum radial distance to the shaft axis. These bottom points also define reversing points of partial oscillational movements of the spray tube 12. The bottom point of each concave surface is also spaced a prescribed radial distance from the shaft axis to define the angular position of the spray tube at a reversing point of tube 12 as cam 20 rotates. Each reversing point is shown graphically by FIGS. 5, 7 and 9 respectively.

Reference may now be made to specific relationships between the convex and concave sections of cam 20. A first convex section 26 includes an apex 32, a second convex section 28 includes an apex 34, and a third convex section 30 includes an apex 36. Positioned between convex sections 26 and 28 is a first concave section 27 having a bottom point 33. Between convex sections 28 and 30 is a second concave section 29 having a bottom point 35. An finally, a third concave section 31 with a bottom point 37 ispositioned between convex sections 30 and 32.

Apex 32 of convex section 26 lies on cam 20 at the outermost radial distance from the cam periphery to the shaft axis. Further, the bottom point 35 of concave section 29 lies on the cam at the nearest distance from the cam periphery to the shaft axis. The difference arrived at by subtractingthe distance between the shaft axis and bottom point 35 from the distance between the shaft axis and apex 32 is the linear amount of rise or fall of the cam surface, relative to the shaft axis, necessary to effect movement of spray tube 12 from one angular limit to the other as set by dial 17.

The angular limits set by dial 18 concide respectively with a first set of reversing points 32a and 35a (FIGS. 4,7) determined by apex 32 and bottom point 35.

The distance from the shaft axis to the remaining apexes 34 and 36 and bottom points 33 and 37 may be described in relation to distances from the shaft axis to apex 32 and bottom point 35. If the distance from the shaft axis to bottom point 35 may be assigned a value A and the distance from the axis to apex 32 assigned to a value B then a distance (B A/2) A or the simplified, B A/2 transmitted to follower 21 could effect a responsive position of spray tube 12 midway between the angular limits set by dial 17.

Apex 34 and bottom point 33 determine a second set of reversing points 34a and 33a of spray tube 12 as shown in FIGS. 6 and 5 respectively. These points are spaced at equal angles to either side of the above described midway position to facilitate equal distribution of water to both included sides. It follows then that the distance from the shaft axis to apex 34 necessary to effect such a position may be defined as (B-l-A/2 )+a where 0: equals the additional distance necessary to efcould then be defined as B A/2 a.

Apex 36 and bottom point 37 (FIGS. 8 & 9) define a third set of reversing points 36a and 37a spaced at equal angles from the midway position and intermediate the set 33a and 34d. The distance to apex 36 from the shaft axis may therefore be defined as'( B A/2 +(a 0) and the distance to bottom point 37 from the axis as(B+A/2 )-(a0 where 6 oz.

The camsurface is designed so that the total included angular movement of the cam while the spray tube moves on one side of the midway position is l 8O..This total includes anumber of separated segments of angular movement during the described reversible pattern of motion, as illustrated in FIG. 10. Assuming constant I velocity of; the can, it then: follows that the average vemidway. positionto reversing points 32a, 34b, and'36a isequalto the average velocity of the tube as itmoves between the midway, positionto reversing points33a, 35a an'd37a (FIG. 10).

In each separate oscillational movement, however, spray. tube 12 accelerates toward the midway, position then decelerates as it moves away from the midway position. Therefore in order to distribute water: evenly,

these oscillational movements must overlap adjacent the midway'position where the velocity of the spray,

tube is relatively high.

The oscillational movements of the spray tube as initiated by one cycle of cam are shown in sequence. by FIGS. 4, 5, 6, 7, Sand .9respectively and are combined to-illustrate a. complete spray cycle in FIG. 10.

r The movement starts with the spray tubeatthe angular limit or reversing point 32a to the. rightof the midway .position (FIG. 4). As the cam rotates, follower. 21'

moves upwardly, pivoting the spray to the left, past th e midway position 1 to reversing-point 33a illustrated in FIG. 5. Follower 21 isthen forced downwardly, as'the cam rotates, to pivot the spraytube to the right, back:

overthe midway position, to the reversing point3411 shown by FIG. 6. The tube then pivots to theleft again past the midway position to the reversing point a and left angular limit shown in FIG. 7. Continued rotation of cam 20 brings tube 12 back* to the right past the mid way position to the reversingv point 36a illustrated in FIG. 8 where pivotal movement of the tube is reversed leftward, overthe midway positionto the reversing:

point 37a shown in FIG. 9 3From this positionthe tube moves back over the midway position to the right angular limit and reversing point 32a of FIG. 4.

It should be noted that the above described sequence of reversing" oscillational movements is completed within one 360 rotation of cam 20.Referring to FIG.

l0,- it may be seen that during this single cycleof cam- 20 the spray of water passes over the midway position six times while passing over the areas adjacentthe angular limits only twice each. Further, the area between reversing points 34a and 36a and the area between-- .6 points 37a and 33a are each passed over four times by the spray.

With the above oscillational movements, the distribution of water from the tube is equalized between the angular limits set by dial 17.

It may become evident from the above description and attached drawings that various changes and modifications may be made therein without departing from the scope and spirit thereof. Therefore, only the following claims are intended to define my invention.

What I claim is:

1 In an oscillating sprinkler of the type including:

a housing:

an elongated: frame extending outwardly from the housing;

a fluid motor mounted within the housing having a drive shaft rotated by an incoming stream of water;

a' perforated spray tube pivotably mounted about a pivot axis on the frame and housing; linkage means operatively connected to the spray tube todefine two predetermined angular limits of motion of the spray tube' about the pivot axis and toirnpart angular movement to the spray tube betweenthe two predetermined angular limits; and drive means for transferring motion from the fluid drive shaft to the linkage; an improvement in the drive means comprising:

motion transmittingmeans operatively connected between the fliiid'motor drive shaft and linkage means for defining a plurality of reversing points angularly located :between the two predetermined-limits at which "the angular motion of the spray tube irnpartedby the linkage means is successively reversed intermediate the two predeterminedlimits to complete a series ofoverlapping movements as the spray tube progresses angularly from one predetermined angular limit to the other.

2. The sprinkler set out in claim 1 wherein the motion .pointsbetween the predetermined angular limits to affect an even distribution of water emited from the spray tube over a: sprinkler pattern as the sprinkler is operate'd.

3. The sprinkler set'out in claim 2 wherein the cam surface is comprised of 'a-series of alternating convex and concave sections angularly spaced about the cam axis.

4. The sprinkler set out inclaim 3 wherein the cam surface includes three convex sections and three interspersed concave sections.

5. The sprinkler set out-in claim 3 wherein the convex sections have apexes and the concave sections have bottom points andwherein' the apexes and bottom points are radially spaced from the cam axis with the apexes being further spaced from the axis than the bottom points.

6. The sprinkler set out in claim 5 wherein the distances from the cam axis to the individual apexes and individual bottom points are "unequal.

. 7. In an oscillating sprinkler of the type including:

a housing;

the improvement in the drive means comprising:

motion transmitting means in the form of a cam fixed to the fluid motor drive shaft and having a continuous cam surface formed thereon, and a cooperative cam follower in engagement with the cam surface and operatively connected to said linkage means; the rise and fall of the cam surface relative to the drive shaft operatively controlling the angular position of the spray tube about its pivotal axis, said cam surface including a plurality of apexes and bottom points alternately located about the drive shaft, whereby rotation of the drive shaft and cam causes the spray tube to progress angularly between its pre-determined angular limits in overlapping reversing fractional movements to concentrate positioning of the spray tube intermediate the respective angular limits of its motion about is pivotal axis.

8. The sprinkler set out in claim 7 wherein the cam surface includes three apexes of unequal height and three bottom points of unequal height, the maximum height of the respective bottom points being less than the minimum height of the respective apexes.

9. The sprinkler set out in claim 7 wherein the cam surface is formed as alternating smooth convex and concave sections. 

1. In an oscillating sprinkler of the type including: a housing: an elongated frame extending outwardly from the housing; a fluid motor mounted within the housing having a drive shaft rotated by an incoming stream of water; a perforated spray tube pivotably mounted about a pivot axis on the frame and housing; linkage means operatively connected to the spray tube to define two predetermined angular limits of motion of the spray tube about the pivot axis and to impart angular movement to the spray tube between the two predetermined angular limits; and drive means for transferring motion from the fluid drive shaft to the linkage; an improvement in the drive means comprising: motion transmitting means operatively connected between the fluid motor drive shaft and linkage means for defining a plurality of reversing points angularly located between the two predetermined limits at which the angular motion of the spray tube imparted by the linkage means is successively reversed intermediate the two predetermined limits to complete a series of overlapping movements as the spray tube progresses angularly from one predetermined angular limit to the other.
 2. The sprinkler set out in claim 1 wherein the motion transmitting means comprises a cam affixed to the drive shaft for rotation therewith about the shaft axis, the cam having a cam surface operatively connected to the linkage means for affecting the series of overlapping movements of the spray tube in response to rotation of the drive shaft and for locating the reversing points between the predetermined angular limits to affect an even distribution of water emited from the spray tube over a sprinkler pattern as the sprinkler is operated.
 3. The sprinkler set out in claim 2 wherein the cam surface is comprised of a series of alternating convex and concave sections angularly spaced about the cam axis.
 4. The sprinkler set out in claim 3 wherein the cam surface includes three convex sections and three interspersed concave sections.
 5. The sprinkler set out in claim 3 wherein the convex sections have apexes and the concave sections have bottom points and wherein the apexes and bottom points are radially spaced from the cam axis with the apexes being further spaced from the axis than the bottom points.
 6. The sprinkler set out in claim 5 wherein the distances from the cam axis to the individual apexes and individual bottom points are unequal.
 7. In an oscillating sprinkler of the type including: a housing; an elongated frame extending outwardly from the housing; a fluid motor mounted within the housing having a drive shaft rotated by an incoming stream of water; a perforated spray tube pivotably mounted about a pivot axis on the frame and the housing; linkage means operatively connected to the spray tube to impart angular movement to the spray tube about the tube axis between pre-determined angular limits; and drive means for transferring motion from the fluid motor drive shaft to the linkage; the improvement in the drive means comprising: motion transmitting means in the form of a cam fixed to the fluid motor drive shaft and having a continuous cam surface formed thereon, and a cooperative cam follower in engagement with the cam surface and operatively connected to said linkage means; the rise and fall of the cam surface relative to the drive shaft operatively controlling the angular position of the spray tube about its pivotal axis, said cam surface including a plurality of apexes and bottom points alternately located about the drive shaft, whereby rotation of the drive shaft and cam causes the spray tube to progress angularly between its pre-determined angular limits in overlapping reversing fractional movements to concentrate positioning of the spray tube intermediate the respective angular limits of its motion about is pivotal axis.
 8. The sprinkler set out in claim 7 wherein the cam surface includes three apexes of unequal height and three bottom points of unequal height, the maximum height of the respective bottom points being less than the minimum height of the respective apexes.
 9. The sprinkler set out in claim 7 wherein the cam surface is formed as alternating smooth convex and concave sections. 